Feeding mechanism for sewing machines



July 24, 192s. 1,618,191

` c. w. MuEL1 ER FEEDING MECHANISM FOR SEWING MACHINES Filed July 19, 192e 4 sheets-sheet 1 July 24', 1928.

. Y c. w. MUELLER FEEDING MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 2 Wow,

Jly 24, 1928. c. w. MUELLER FEEDING MECHANISM FOR SEWING MACHINES File'd July 19, 1926 4 S1'1eel'.S-Sheel'l 3 SW m July 24, 1928.

C. W. MUELLER FEEDING IECHANISM FOR SEWING MACHINES Nets-Sheet 4 e J 3m@ fl J @Maaik/Manz l 3&1:

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F 7 l Q Patented July 24, 1928.

UNITED 'STATES PATENT OFFICE,

CHARLES w. MUELLER, OE sfr. LoUIs,"IvIIssOUnI, AssIGNoR TOJLEWIS ,INVISIBLE STITOIIMAOIIINE COMPANY, Orsi?. LOUIS, MISSOURI, A CORPORATION or MAINE.

rnnnIN'cf iuncHANIsi/I ron SEWING MACHINES.

'Application filed Iuiy 19,

f This invention relates to new anduseful improvements in feeding mechanisms for sewing machines generally, althoughthe invention is more particularly directed to a top feeding Vmechanism for blindstitch sewing. machines.

The principal object of my inventionis to provide a feeding mechanism wherein the feed dog is intermittently given the usual 4- niotions, thatis up and down and hack and forth, through the medium of a 3-point cam whereby the feeding stroke of the dog will be made in a substantially horizontal line.`

Another object of the invention lies in the provision of a feeding mechanism of the character described which includes an actuatl supporting plate 11 andy plunger 12. The

. ing lever having direct contact with the feed dog and with the 3-point cam, and having anadjustable fulcrum for varying the length of the feed stroke of the dog. l f

` Another object Of the inventionlies inthe provision of a top feeding mechanism particularly adaptable forblindstitch sewing machines,aiid wherein said feeding mecha- ,nism is supported by the overhanging arm and directly in rear of the stitch forming mechanism whereby the entirety occupiesbut very littlespace.

`-l/Vith these and other objects in view which will more fully appear the nature oftheinvention will be more clearly understood by following the description,` the appended claims, and the several views illustrated in the accompanying drawings, in which v Figure 1 is a side elevation of a blindstitch sewing machine equipped with my improved `feeding mechanism, v

Figure 2 is an enlarged front elevationof Ythe stitchinghead and showing'the feeding mechanism associated therewith, y Figure 3 is an enlargedend elevation of the sew-ing head. and showing the feeding mechanism, r*

n Figure A is `an enlarged sectional view taken iii the line of feed, f

Figure 5 is aV horizontal l sectional vie taken on the line 5 5 of Figure 4, and

Figure 6 is a diagrammatic'viewxillustrating the A-inotioii path of travel of the feed ,dog through the mediumv of the 3-point cam.

Figure 7 is adetailed view partly, in section showing the mounting of the cam on its shaft. y

)Like numerals designate corresponding i926. seiiai No. 123,376.

trated in the patent to Mueller 1,539,399,

May 26, 1925. This machinecoinprises a frame including a standard 5, a lower Or work arm 6, and an upper Overhanging arm 7 the latter being provided at its end with adownward extension 8 which terminates adjacent the outer end of the lowerarm 6 and carries a fixed presser foot 9. Above the presser foot 9 is disposed the stitch forming mechanism 10, and below.` the presser foot 9, and carriedby'the lower arm k6, is the `work platell and plunger 12`are connected and `Operated in the usualmannerand further delscriptionthereof is unnecessary;

front of and in spaced relation to the depending extension 8 of the frame. Inasinuch in v the accompanying drawings, is identical with that showny in the Mueller patent supra,

it is. deemed to be unnecessary tO describe the saine in detail. y l

Cooperating wtih the stitch forming mechanism. to intermittently feed the material, is

liiie'chanisni 10, the latter being located in Y as this stitch forming mechanism, as shown f a feeding mechanism which forms the subject matter of this invention. This feeding mechanism-includes a feed doglli which is detachably connected to the lower end' of an ,actuating leverl. Thislever isdi'sposed in n the spaceybetween the downward extension 8 oftheframe andthe stitch forming mechanism 10. The longitudinalaxis of the lever is disposed ina vertical plane and the lever kis provided at its upper endl with afcam follower 16 for embracing a3-point"cani 17 `fined to the main shaft '13, u The cam "17 is provided with three points a, b and c respectively. The lever 15has a sliding connection with a shiftable fulcrum'block 18.` Theblock 18 is provided with a tongue which has sliding engagement in a groove119 formed inthe outer-end face of the downward extension 8 of thek frame; This Agroove 19 `extends upwardly and rearwardly for a purpose hereinafter described. The block 18 is formed with an elongated slot 18L through which a set screw 18b projects for engagement withV the frame extension 8 and thereby secure the block 18 in any position of adjustment. The block 18 has a forwardly extending integral ear 20 to which is pivotally Connected, as at 21, a sleeve 22 which embraces the lever 15. Thus as the cam 1'( rotates, the lever 15 will be raised and lowered and also oscillated back and forth in the lineof feed.

The high and low points of the cam 17 are concentric and consequently when the feed lever is raised or lowered, the oscillation thereof, ywhile the feed dog is in either of said positions, will result in the feed dog having a substantially straight horizontal movement. This is particularly true by reason of the fact that the fulcrum 21 of the lever is located at a point welll removed from lthe feed dogand consequently the arc described by the feed dog is yof such .a radius as to be substantially straight and horizontal.k It will be also noted that by means of this S-pointfcam, the feed motion of the dog is practically a square motion, as indicated by the lines cl, c, f, g, in Figure 6. AThe line g yindicates thesubstantially straight horizontal feed7 stroke or motion, the line g cl indicates the up movement of the dog, the line d e indicates the backward movement of the dog, and the line 'c 7 indicates the down movement `of the dog- This motion is advantageous in that it permitsthe dog to be raised vertically from the work instead of having a tendency to draw the work towards the needle.

The stitch formingmechanism 10 yincludes a sleeve 23 which entendsr forwardly of the downward extension 8 of the frame yand forms a support for the needle lever 24 and also al journal for the thread looperactuating` shaft 25. The sleeve 23 is disposed directly above the presser foot 111 and the feed lever 15 is provided with a yoke 26 which .straddles vsaid sleeve 23. y

From the foregoing it will be observed that .the block 18 is shown as being at the upper end of its adjustment and consequently the fulcrum 21 is'located at its highest so as 'to 'impart the maximum feedv travel to the feed dog. It will be observed that if 'the fulcrum block 18 were moved downwardly in a straight vertical plane, the feed travel would notonly be shortened but also the feed movementwould be lequally divided on opposite sides of a vertical plane containing said fulcrum. Thus under these circumstances the feed dog would begin its feed stroke at points farther and farther iny rear of the needle, depending of course 'upon' theV adjusted position of the fulcrum 21. This objection is overcome by inclining the groove 19 upwardly "and rearwardly. As' a result, when the block 18 is lowered-it will also be mOved'fOlWa-ldly so that the .feed stroke will always begin at the same point relative to the positionof the needle. Consequently, Ii.

have provided a fulcrum for the lever which is shiftable in two directions, namely, vertically and horizontally, the fulcrum being shiftable in both directions simultaneously.`

From the foregoing, it will be seen that termediate the stitch` forming mechanism and the depending portion of the overhang- `ing arm, thus 'forming a very compact mechanism which occupies but very little space.

Itis Aof course tobeunderstood that the details of structure and arrangements of parts may be variously changed and ymodified .withoutLdeparting from thespiritand scope of my invention.

T claim:

1. 'A feeding mechanism forsewing machines comprising in combination, ai feed dog, a rotary shaft, 'a S-point cam fixed on said shaft, and an actuating' connection between the dog and'shaftjcomprising-a lever having a sliding fulcrum and/connected at its ends directly tosaid dog and camfrespectively for imparting during each rotation of said cam four' moti-ons to the dog including a substantially straight horizontal feeding mot-ion, said fulcrum ybeing adjustable longitudinally and transversely of the lever to respectively vary the length of the feed- -motion ofthe dog and yto maintain the inil feed stroke thereof at a tial point of the fixedpoint. y' j f 2. In a sewing machine, the combination with a work supporting arm and an overhanging arm, of a xed presser foot fixed to lthe overhano'infr arm and dis osed ad'acent c7 n f, y

the work supporting arm, a rotary shaft journaled in the 4overhanging arm, a top feed.

dog cooperating withthepresser foot and worksupporting arm, a earn fixed to `the main shaft, and avertically disposed lever fulcrumed on the overhanging army and having directL connections with the feed ydog and cam for imparting intermittent four motion movements .to saiddog, ysaid lever being fulcrumed4 on a block adjustably mountedon'the overhanging arm for vertical and lateral movements for varying the kfeed i travel of the dog and maintaining the initial starting point of the 'feed travel at a fixed point.

A feeding mechanism for sewingmachines, comprising in combination a feed dog, a rotary shaft, an actuating lever directly connectedto the feed dog, and having operative connectionl withgsaid shaft, and a fulcrum for-the'lever adjustable longitudinally and transversely ofthe leverto respectivelyvary the length of the feedl motion 'of the dog and to maintain `theinitial point of the feed stroke thereof at a fixed point.

4. A feeding mechanism for sewing machines, comprising in combination a frame, a feed dog, a rotary shaft journaled 1n the frame, an actuating lever direct-1y connected with the feed clog and having operative oonneetion kwith said shaft, said frame being provided With a groove inclined to the axis of the lever, a fulcrum block for the lever 10 In testimony whereof hereunto ax my 15 signature.

CHARLES W. MUELLER. 

